For the Sundays at the Met program An Old World Art Form for the New World: Issues in the History of Conservation, Collecting, and American Designs for Stained-Glass Windows, a group of experts, conservators and curators explore the history of stained glass, from its creation to its conservation, its design to its collection.

Ivo Rauch discusses the complex work of conserving stained glass today, paying particular attention to a critical first step: deciding what is worthy of conservation. He describes both the factual and philosophical qualifiers that determine the value of an artwork, considering everything from rarity and renown of the artist, to the German philosopher Walter Benjamin’s concept of a work’s aura: its unquantifiable presence in time, space, ritual, and tradition.